ASW 15 / Astir CS mid-air on crossing climb tracks — FLARM not heeded

In a mid-air collision near Lueneburg, the pilot of an Astir CS was seriously injured; the ASW 15 landed damaged and the Astir crashed unmanned in a residential area. Both gliders had departed Lueneburg cross-country and climbed for 18 s on nearly straight crossing tracks (81 deg). The ASW 15 received a FLARM warning of traffic behind and turned right; the Astir CS continued slightly right-banked. Neither pilot saw the other on the constant-bearing approach and the FLARM warnings were not acted on. After the collision the Astir entered a near-vertical, partly inverted descent and the pilot bailed out.

1. Thermaling cross-country: After separate launches from Lüneburg, the ASW 15 pilot climbed to about 1,100 m and proceeded on his planned 450 km cross-country flight while thermaling under cumulus clouds.
2. Shared thermal area: Both gliders were operating in nearby thermals on similar routes without team-flying coordination or mutual radio contact in Class E airspace.
3. Converging flight paths: In the last 18 seconds before impact, the ASW 15 and Astir CS flew nearly straight on crossing tracks with an 81° angle and small height gain, bringing them into conflict.
4. FLARM alert and turn: The ASW 15 pilot received a FLARM collision warning showing another aircraft 380–500 m behind and then turned right under the next cloud at about 1,097 m AGL, while the Astir CS continued with a slight right movement centering the next thermal.
5. Mid-air collision: As the ASW 15 turned and the Astir CS flew in a slight right attitude, the two gliders collided at approximately 1,097 m AGL about 2,100 m northwest of Lüneburg, causing major structural damage to both aircraft.
6. Emergency descent actions: The ASW 15 entered a dive but the pilot recovered control and conducted a control check, while the Astir CS entered a near-vertical, partly inverted descent, prompting its pilot to jettison the canopy, release his harness, fall clear, and deploy his parachute.
7. Crash - serious injury: The ASW 15 pilot, not wearing a parachute, landed the heavily damaged glider back at Lüneburg without injury, whereas the Astir CS crashed unmanned into a residential area and was destroyed, and its pilot, descending under a parachute that later tore and began rotating, impacted a wheat field and sustained serious back injuries.